Multicolor Particle Research Articles

Visualization of Water Toroidal Vortex by Multicolor Particle Image Velocimetry

Visualization of Water Toroidal Vortex by Multicolor Particle Image Velocimetry

Development of the optical electronic setup for carrying out measurements by multicolor Particle Image Velocimetry

The paper is devoted to development of the optical electronic setup for carrying out measurements by multicolor particle image velocimetry. The main advantage of this method is the ability to visualize vector velocity fields in several planes simultaneously. As a result a 3D model of a setup was developed, a laboratory sample was assembled and series of testing experiments were performed. As a test object, vortex structure formed by a chemical stirrer in a cuvette with liquid has been considered. The experimental data were compared with the computer model developed in SolidWorks and FlowVision software.

Multiplexed PSF Engineering for Three-Dimensional Multicolor Particle Tracking.

Three-dimensional spatiotemporal tracking of microscopic particles in multiple colors is a challenging optical imaging task. Existing approaches require a trade-off between photon efficiency, field of view, mechanical complexity, spectral specificity, and speed. Here, we introduce multiplexed point-spread-function engineering that achieves photon-efficient, 3D multicolor particle tracking over a large field of view. This is accomplished by first chromatically splitting the emission path of a microscope to different channels, engineering the point-spread function of each, and then recombining them onto the same region of the camera. We demonstrate our technique for simultaneously tracking five types of emitters in vitro as well as colocalization of DNA loci in live yeast cells.

Investigation of the Jet Liquid Flows Structure by Multicolor Particle Image Velocimetry

Investigation of the Jet Liquid Flows Structure by Multicolor Particle Image Velocimetry

High-Throughput Super-Resolution Microscopy for Revealing Molecular Architecture

Single molecule localization microscopies (SMLM) occupy a special niche in the biologist's toolbox because they can achieve among the highest resolutions in fluorescence microscopy. Yet, many important biological questions remain out of reach due to challenges in acquiring and analyzing statistically significant SMLM datasets. Previously, we created high-throughput PALM by building an automated microscope to image hundreds of bacteria cells, live, 3D, and across cell cycle. To complement this, we created a uniform illumination scheme to enable large field of view images. More recently, we have been working toward autonomous microscopy, reducing the number of user inputs and increasing the responsiveness of the microscope to the sample using machine learning and engineering approaches. We demonstrate the power of this approach for studying macromolecular complexes within cells. To study the organization of such complexes, particle-based analysis has proven to be powerful, but has been limited so far by difficulties in generating large multi-color particle libraries, as well as the complexity of orientational alignment. We have addressed both challenges and, as a result, present a novel framework and software for deciphering the 3D organization of protein complexes composed of multiple components.

Open LED Illuminator: A Simple and Inexpensive LED Illuminator for Fast Multicolor Particle Tracking in Neurons.

Dual-color live cell fluorescence microscopy of fast intracellular trafficking processes, such as axonal transport, requires rapid switching of illumination channels. Typical broad-spectrum sources necessitate the use of mechanical filter switching, which introduces delays between acquisition of different fluorescence channels, impeding the interpretation and quantification of highly dynamic processes. Light Emitting Diodes (LEDs), however, allow modulation of excitation light in microseconds. Here we provide a step-by-step protocol to enable any scientist to build a research-grade LED illuminator for live cell microscopy, even without prior experience with electronics or optics. We quantify and compare components, discuss our design considerations, and demonstrate the performance of our LED illuminator by imaging axonal transport of herpes virus particles with high temporal resolution.

Multicolor particle shadow accelerometry

This paper describes the extension of multicolor particle shadow velocimetry (CPSV) to the measurement of local acceleration in an Eulerian frame of reference. A validation experiment was conducted on a pendulous disk undergoing unsteady rigid body rotation. Angular velocity and acceleration profiles by CPSA are presented along with a comparison to recordings by an accelerometer mounted on the pendulum. CPSA is also demonstrated in a fully-developed turbulent pipe flow. Profiles of standard deviation of the local acceleration in the near wall region are compared to similar measurements by Christensen and Adrian. A favorable comparison is found between CPSA and particle image accelerometry (PIA). The effect of acceleration time delay, or the time between two velocity estimates, on local acceleration estimates is discussed.

Correcting for color crosstalk and chromatic aberration in multicolor particle shadow velocimetry

Color crosstalk and chromatic aberration can bias estimates of fluid velocity measured by color particle shadow velocimetry (CPSV), using multicolor illumination and a color camera. This article describes corrections to remove these bias errors, and their evaluation. Color crosstalk removal is demonstrated with linear unmixing. It is also shown that chromatic aberrations may be removed using either scale calibration, or by processing an image illuminated by all colors simultaneously. CPSV measurements of a fully developed turbulent pipe flow of glycerin were conducted. Corrected velocity statistics from these measurements were compared to both single-color PSV and LDV measurements and showed excellent agreement to fourth-order, to well into the viscous sublayer. Recommendations for practical assessment and correction of color aberration and color crosstalk are discussed.

Adaptation of Multicolor Particle Contact Detection Method for DEM and Performance Evaluation with Multicore Processors

Adaptation of Multicolor Particle Contact Detection Method for DEM and Performance Evaluation with Multicore Processors

Multicolor Dye-Doped Silica Nanoparticles Independent of FRET

Multicolor particles were prepared by incorporating two dyes, one fluorescent (fluorescein isothiocyanate) and one phosphorescent (tris(1,10-phenanathroline) ruthenium ion), into the silica matrix. Colors of the particles can be easily tuned by either varying the doping ratios of the two dyes or changing the excitation wavelength while fixing the ratios. The multicolor character of the particles is less sensitive to the location of the two dyes in the silica, since the luminescence of the particles is independent of Förster resonance energy transfer (FRET).

Simultaneous measurement of concentrations and velocities of submicron species using multicolor imaging and microparticle image velocimetry

We propose a novel approach to resolve simultaneously the distributions of velocities and concentration of multiple, submicron species in microfluidic devices using microparticle image velocimetry, and particle counting. Both two-dimensional measurement and three-dimensional analysis of flow fields, from the stacked images, are achieved on applying a confocal fluorescence microscope. The displacements of all seeding particles are monitored to determine the overall velocity field, whereas the multicolor particles are counted and analyzed individually for each color to reveal the distributions of concentration and velocity of each species. A particle-counting algorithm is developed to determine quantitatively the spatially resolved concentration. This simultaneous measurement is performed on a typical T-shaped channel to investigate the mixing of fluids. The results are verified with numerical simulation; satisfactory agreement is achieved. This measurement technique possesses reliability appropriate for a powerful tool to analyze multispecies mixing flows, two-phase flows, and biofluids in microfluidic devices.

Multiframe Particle Tracking in Intravital Imaging: Defining Lagrangian Coordinates in the Microcirculation

The cellular composition of the microcirculation creates blood flow that can be unsteady and nonuniform. To obtain information about nonuniform cellular trajectories, we describe in vivo imaging techniques that provide both detailed tracking of individual particles as well as an approach to simultaneous multicolor particle tracking. Particularly relevant to biologic systems, Lagrangian methods provide information about the fate of individual particles and flow in the system.

Multicolor particle systems with large threshold and range

In this paper we consider the Greenberg-Hastings and cyclic color models. These models exhibit (at least) three different types of behavior. Depending on the number of colors and the size of two parameters called the threshold and range, the Greenberg-Hastings model either dies out, or has equilibria that consist of “debris” or “fire fronts”. The phase diagram for the cyclic color models is more complicated. The main result of this paper, Theorem 1, proves that the debris phase exists for both systems.